Can Common Virus, Lack of Sunlight Boost MS Risk?

MONDAY, April 18 -- Infection with mononucleosis -- the easily spread virus that's the bane of many college students -- and little exposure to sunlight may combine to boost a person's risk for developing multiple sclerosis, a new study suggests.

"MS is more common at higher latitudes, farther away from the equator," the study's lead researcher, Dr. George C. Ebers, of the University of Oxford in England, said in a statement provided by the American Academy of Neurology. "Since the disease has been linked to environmental factors such as low levels of sun exposure and a history of infectious mononucleosis, we wanted to see whether the two together would help explain the variance in the disease across the United Kingdom."

The researchers examined hospital admissions in England's National Health Service over a seven-year period and focused on 56,681 cases of multiple sclerosis and 14,621 cases of infectious mononucleosis. The researchers also examined statistics from NASA about the levels of ultraviolet light in England.

They found that exposure to sunlight and to the mononucleosis virus seemed to explain almost three-quarters of the difference in levels of MS across the United Kingdom. Sunlight exposure alone appeared to explain 61 percent of the total variance.

"It's possible that vitamin D deficiency may lead to an abnormal response to the Epstein-Barr virus," which is linked to MS, Ebers said. Sunlight exposure boosts levels of Vitamin D.

"More research should be done on whether increasing UVB exposure or using vitamin D supplements and possible treatments or vaccines for the Epstein-Barr virus could lead to fewer cases of MS," Ebers said.

The study appears in the April 19 online edition of Neurology.

More information

The U.S. National Institute of Neurological Disorders and Stroke has more about multiple sclerosis.